This invention relates to a torque motor and, more particularly, to a torque motor having a combined shield ring and rotor ring.
A mechanical actuator is a device that controllably produces a mechanical movement. The mechanical actuator is typically connected to another device which requires such a movement for its proper operation. Mechanical actuators can be designed to produce linear, rotational, or other types of movements, as required, and the present invention deals with a rotational actuator or torque motor.
One type of torque motor includes a set of electromagnet rotor coils affixed to a stationary annular support ring in a symmetric configuration. A set of corresponding permanent magnets is affixed to a rotationally movable shaft lying within the support ring, with the permanent magnets in a generally facing but angularly displaced relationship to the electromagnet rotor coils. A ferromagnetic stationary flux shield overlies the annular support ring.
This conventional torque motor is operable, but has limitations resulting from its design. The inventor has recognized that the flux shield magnetically reacts with the magnetic field produced by the rotating permanent magnets due to induced magnetic coupling. This magnetic coupling reduces the efficiency of the torque motor by a substantial amount.
There is a need for an improved approach to the design of a torque motor having improved efficiency. The present invention fulfills this need, and further provides related advantages.